Ductility testing apparatus



M W40. c. s. HOWE DUCTILITY TESTING APPARATUS Filed Oct. 1, 1958 2Sheets-Sheet l lllmlmnnnl l TTORNEVS.

Jan. 2, 1940. c. s. HowE 2,185,340

DUCTILITY TESTING APPARATUS Filed Oct. 1, 1938 2 Sheets-Sheet 2 lig. 6.

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FOR THE @M lil ,Y thread before breaking. It has also been foundPatented `ian.. 2, 1940 UNITED STATES PATENT oFrlcE IndustrialDevelopments Incorporated,

Los

Angeles, Calif., a corporation Application October 1, 1938, Serial No.232,850v

6 Claims.

lViy invention relates to'material testing de. vices, with particularreference to apparatus for ascertaining the ductility of asphaltic,bituminous, and like materials, and is a continuationin-part of myco-pending application entitled Duptility testingapparatus, Serial No.180,372, filed December I7, 1937.

In accordance with the standard procedure specified by the AmericanSociety for Testing Materials, the ductility rating of a bituminoussubstance is determined by noting the length a standard sample may bestretched without breaking at 5 cm. per minute in a water bath at 25 C.

For special purposes, other rates and other temperatures may bespecified. In the usual practice, the sample is immersed in an elongatedtank with one end of the sample held fixed and the other end engaged bya carriage that traverses the tank at the standard rate ofspeed.

` The present invention is directed primarily to the means formechanically relating the carriage to the tank and to the means foractuating the carriage.

lin oneA of the well known devices oirthe prior art, the carriage ismounted on and moved by a pair of immersed screws extending lengthwiseof the tank. The turbulence in the water caused by the rotation of thesescrews, and by their vibration, interferes with visibility oi theimmersed sample, a fact particularly objectionable since a sampleusually stretches to an exceedingly fine that such turbulence may causepremature breaking of such a thread. A further disadvantage of the screwdrive is a certain inconvenience involved in shifting the carriage backto the starting point after completion of a test, it being necessary todisengage the carriage and then to adjust the carriage for newengagement at the zero point ci the ductility scale.

One of the objects of my invention is to provide a drive arrangementthat will avoid turbulence in the water bath especially in the vicinityof the breaking point of the sample under test.

A further object is to provide a drive arrangement that will involveminimum inconvenience in returning the carriage to its starting point,in contrast to the screw drive described above, and

in contrast to other types oi drive known to the art.

An additional object is to simplify the driving mechanism of such atesting device. Under this heading, I-propose to eliminate the problemof transmitting power from a fixed power unit to a moving carriage, toreduce the size of power unit required, and to minimize vibration of atank by a power unit. Such vvibration is markedly noticeable where longdriving screws span the length of a tank, and is appreciable wheneverany type of power unit is mounted directly on a tank.

A feature of my invention is the conception that all of the aboveobjects of my invention may be attained by a construction in which thepower unit is mounted directly on the carriage to make the carriage aself-contained unit.

The above and other objects and advantages of my invention will beapparent in the description to follow taken with the accompanyingdrawings.

In the drawings:

Fig. 1 is a pianview of my apparatus.

Fig. 2 is a side elevation of the apparatus, with the tank partiallybroken away.

Fig, 3 is a transverse section slightly enlarged taken as indicated bythe line 3-3 of Fig. 2.

Fig. 4 is a fragmentary section greatly enlarged 20 taken as indicatedby the line 4--4 of Fig. 2. Fig. 5 is a perspective view of the mold forforming a briquette of material to be tested.

Fig. 6 is a View similar to Fig. 3, with certain parts broken away,showing a modication of the 25 carriage drive.

Fig. '7 is a fragmentary plan view showing a second modiiication of thecarriage drive.

The drawings show a tank I0 suiciently elongated to permit stretching asample 110. cm. for 30 example, the tank preferably being made ofmaterial providing relatively rigid side walls Il. The tankeis providedwith a drain outlet I2 normally closed by a plug i3, and in servicecontains a body of water i4 to a level I5. Suitable means, 35 not shownin the drawings but well known to the art, may be employed to controlthe temperature of the water automatically, such means preferablyincluding a thermostat responsive to the water temperature. o

Fixed to an end wall I6 of the tank is a submerged horizontal plate ilcarrying upwardly extending pins I8. 0n the same level is a similarplate i9 having corresponding pins 20, this second plate being carriedby a wall member 2l de- 45 pending from the platform 22 of a carriagegenerally designated by the numeral 23.

Preparatory to a test, the material to be rated is formed by thestandard procedure into a briquette by a moldv constructed as shown inFig. 50 5. The mold comprises four pieces, clips 24 and 25 at the endsand an intermediate pair of side blocks 26,. After a briquette of thethickness of the mold is formed in the conguration indicated, the eye210i the clip 24 is inserted on a xed pin 55 I8, and the eye 28 of theclip 25 is engaged with the corresponding pin 20 that' moves with thecarriage 23. The two side blocks 26 are then removed, leaving thebriquette engaged by the end clips 24 and 25. 'I'he briquette is thenstretched toits breaking point by movement of the carriage. More thanone briquette may be stretched simultaneously.

To` ascertain the length of the Sample at the breaking point, ahorizontal scale 29 is mounted on an angle-iron 30, the angle-iron beingsecured to one of the side walls I l. A pointer mounted on the carriageto traverse this scale may comprise an arm 32 secured by a thumb-screw33 in an adjustable manner to permit accurate positioning of the pointerat the zero point of the scale.

I'he present invention is characterizedv by the conception of mountingthe carriage on rails at each side of the tank, preferably at least oneof the rails being in the form of a rack to provide positive tractionfor driving the carriage. In the preferred form of the invention shownin the drawings, both of the rails are racks. One of the rails or racks34 is mounted on the aforementioned angle-iron 30 by screws 34a andsleeves 34h, and the other rail or rack 35 is mounted on a similarangle-iron 36 by screws 35a and sleeves 35h on the opposite side wall Ilof the tank. Preferably the sleeves 34h and 35b are of rubber or otheryielding material. Journaled in bearings 31 on the bottom face of thecarriage platform 22 are two spaced shafts, a shaft 38 having pinions 39keyed to its opposite ends, and a shaft 40 carrying pinions 42. Thesepinions engage the racks 34 and 35 on opposite sides of the tank andsupport the carriage 23.

The shaft 38 is driven by a suitable motor 43, which may be of thesynchronous type. A speed reduction unit 44 is combined with the motorand further speed reduction may be had by providing a relatively smallpinion 45 on the end of the shaft 46 driven by the speed reductionmechanism, the small pinion 45 engaging a relatively large gear 41 keyedto the shaft 38 under the carriage platform. Since the gear 41 extendsbelow the water level I5, it is desirable to enclose the gear in acircular housing 48 secured to the carriage platform 22. No turbulenceproblem is involved because any disturbance of the water occasioned bymovement of the housing 46 is remote from the sample being tested, andsuch disturbance is insignificant since no rotary motion is involved,the housing merely moving through the water in a straight line at theusual relatively slow testing speed of 5 cm. per minute.

In the preferred form of my invention shown in the drawings, the circuitfor energizing the motor 43 includes a pair of conductors extendinglongitudinally of the tank. These conductors are shown as two strips ofmetal 49 embedded in some non-conducting material, such as a strip ofwood 50, the wooden strip resting on the angleiron 36 between the rack35 and the side wall Il of the tank. It will be noted that theinsulating material protects all but the upper edges of the twoconductors, and that these upper edges are given some measure ofprotection by the fact that they are positioned in the recess formed bythe rack and the wall of the tank. There is very little likelihood of anoperator touching either of the two conductors by accident.

Cooperating with the two conductors 49 are two corresponding brushes orcontact elements 62 that extend downward through suitable apertures in acontact housing 53 of insulating material mounted on the undersurface ofthe platform 22. To keep the contact elements 52 from dropping throughthe housing when the carriage is lifted from the rack, the inner ends 54of the contact elements are enlargedas indicated in Fig. 4. To providefor a desirable downward pressure against the contact elements, helicalsprings 55 may be confined between the inner ends 54 of the contactelements and set-screws 56. A switch for controlling the motor circuitmay be located anywhere on the tank or on the carriage. In the drawings,such a switch 51 for manual control is located on the carriage platform22.

'Ihe procedure for ascertaining the ductility rating of a sample will beclear from the foregolng description. Movement of the carriage away fromthe end wall I8 of the tank stretches the sample S with minimumdisturbance of the water bath. Since the carriage is a self-containedunit that simply rests upon the tank, at the end of a test the carriagemay be lifted from the rack, becoming entirely free and independent ofthe tank. and then may be replaced on the tank at the zero end of thescale to start a new test. It will be apparent to those skilled in theart that to lift the carriage from the rack and replace it at the newposition is an exceedingly simple procedure.

It will be noted that the motor and the drive mechanism are disposed todiscourage the transmission of vibration to the body of water in thetank. In the first place, the motor and the speed reduction mechanismare mounted on the platform 22 of the carriage, being thereby removedfrom direct contact with the tank. It will further be noted that thetank walls are relatively rigid and that any vibration from the carriagemust be transmitted to the tank through the yielding sleeves 34h and35h, and through the angleirons 36 and 36, these angle-irons beingdisposed to favor absorption of motor vibration. Preferably theangle-iron members 30 and 36 will be relatively thin to provide adesirable degree of exibility. A further feature of my invention in thedirection of vibration reduction is the employment of a relatively lowpowered prime mover made possible by my construction.

Fig. 6, showing a modified driving arrangement for the carriage 23, issimilar to the above-described form of my invention, correspondingnumbers being employed to designate corresponding parts. In this form ofmy invention the drive shaft 38a has keyed to opposite ends thereofdriving pinions 60, and has mounted thereon, preferably for independentrotation, a pair of flanged supporting wheels 8| whereby the functionsof driving the carriage and supporting the carriage are separated. Oneach side of the carriage the pinion 60 at the end of the shaft 38aengages a rack 63 and the flanged wheel 6| on each side of the carriagerides upon a corresponding rail 64 for supporting the carriage. Thesecond shaft 46a of the carriage has a flanged supporting wheel 65 ateach of its ends riding upon the corresponding rail 64 to cooperate insupporting the carriage. In this modified form of my invention the motoris energized directly through conductors in a suitable flexible cable61.

A second modification of driying arrangement for the carriage issuggested by Fig. '7 in which parts previously described are givencorresponding numerals. In this particular form of my invention a pairof spaced supporting shafts 68 is employed, only one of which is shownin Fig. 7. Each of the shafts 68 carries on each of its ends asupporting wheel 63 for the carriage that rides upon a correspondingrail '10. A drive shaft l2 that is driven by the aforementioned gear ilactuates a pinion 'I3 on each end of the shaft, the pinion being inengagement with a corresponding rack 14.

All the forms of my invention are characterized by the conception of aself-propelled carriage adapted to travel along the tank. It isimportant to note that the length of the tank may be extendedindennitely without complications, Whereas diiiiculties would arise werethe carriage driven by screws or cables actuated from some stationarypoint.

My description of the specific forms of the invention for the purposesof this disclosure will suggest to those skilled in the art variouschanges and modifications that do not depart from the spirit of myinvention. I reserve the right to all such changes and modicationswithin the scope of my appended claims.

I claim as my invention:

1. A ductility testing device of the character described, comprising: atank; a carriage mounted on the tank; means xed within the tank toengage one portion of a test sample; means on the carriage to engage anopposite portion of the test sample; and a power unit mounted on thecarriage to move the carriage along the tank to stretch said testsample, said carriage being removably supported by the tank whereby thecarriage may be lifted from the tank after a test and replaced thereonat a starting point for a subsequent test.

2. A ductility testing device of the character described, comprising: atank; at least one rail on each side of the tank, at least one of saidrails being in the form of a rack; a carriage; wheel means supportingthe carriage on said rails; driving means carried by the carriage forengagement with said rack; a motor mounted on the carriage andoperatively connected with said driving means; means xed within the-tank to engage one portion of a test sample; and means on the carriageto engage an opposite portion of the test sample, whereby the sample maybe stretched by movement of the carriage.

3. A ductility testing device of the character described, comprising: atank having relatively rigid side walls; rail means on each side of thetank, including at least one toothed driving rail; a carriage; wheelmeans on the carriage engaging said rails to support and drive thecarriage, including a toothed Wheel meshing with said driving rail;a,motor mounted on the carriage and connected with said wheel to drivethe carriage; means fixed within the tank to engage one portion of atest sample; means on the carriage to engage an opposite portion of thetest sample, whereby the sample may be stretched by movement of thecarriage; and a scale to indicate the distance the carriage moves instretching a sample.

4. A ductility testing device of the character described, comprising: atank having relatively rigid side walls; rail means on each side of thetank, including at least one toothed driving rail; means yieldinglysupporting said rail means on the tank; a carriage; wheel means on thecarriage engaging said rails to support and drive the carriage,including a toothed wheel meshing with said driving rail; a motormounted on the carriage and connected with said wheel to drive thecarriage; means xed within the tank to engage one portion of a testsample; means on the carriage to engage an opposite portion of ythe testsample, whereby the sample may be stretched by movement of the carriage;and a scale to indicate the distance the carriage moves in stretching asample.

5. A ductility testing device of the character described, comprising: atank: a pair of rails, one on each side of the tank; a carriage; wheelssupporting said carriage on said rails; rack means supported by thetank; gear means on the carriage engaging said rack; a motor mounted onthe carriage to drive said gear; means fixed within the tank to engageone portion of a test sample; means on the carriage to engage anopposite portion of the test sample, whereby the sample may be stretchedby movement of the carriage; and a scale to indicate the distance thecarriage moves in stretching a sample.

6. A ductility testing device of the character described, comprising: atank; at least one rail on each side of the tank, at least one of saidrails being in the form of a rack; a carriage; wheel means supportingthe carriage on said rails; driving means carried by the carriage forengagement with said rack; a motor mounted on the carriage andoperatively connected with said driving means; means iixed Within thetank to engage one portion of a test sample; means on the carriage toengage an opposite portion of the test sample, whereby the sample may bestretched by movement of the carriage; and a circuit for energizing saidmotor, said circuit

